my74ls4

Pulled the body off the frame. The problem I have is if you look at the car from behind the left side of the windshield frame appears to be about 1 1/2" lower than the right side. At first I thought the frame was bent but it isn't. I looked at the body after I removed it from the frame and it is still noticable. Is there any way to take measurements to confirm if the windshield frame is bent? I am also considering getting a complete body to replace this one. What other years could I look for that would fit if I decide to swap the body. I have a 74 coupe that needs an awful lot of body work.